Method of making stamped clamps



Dec. 1, 1931. F. D. WENN 1,834,663

METHOD OF MAKING STAMPED CLAMPS Filed May 15, 1931 3 Sheets-Sheet 1 INVENTOR i I 7 10 6/ Ell/ rin. y 4 i, Maw? HIS ATTORNEY Dec. 1, 1931. w 1,834,663

METHOD OF MAKING STAMPED CLAMPS Filed May 15, 1931 3 Sheets-Sheet 2 M Z1 145 10 Z1 lNVENTOR W HIS ATTORNEY Dec. 1, 19 31. wE 1,834,663

METHOD OF MAKING STAMPED (EL-AMPS Filed May 15, 1951 s Sheets-Sheet s I 10 57 f f I I w gm m k J J INVENTOR afnh.

HIS ATTORNEY Patented Dec. 1, 1931 unrrsn STATES,

PATENT oFFicE.

rLoYnn. warm, or BiNGI-IAMTON, NEW YORK, ASSIGNOR 'ro THE BREWER-TITOH'ENER CORPORATION, orooa'rLANn, new YoaK, A oonroaarrou or uEwYoRK METHOD-Ion MAKING STAMPEZD .cLAMrs A plicationpfiieanay 1931. semi No. 537,540.

This invention generically relates to the art of metal swaging, and more particularly pertains to an improved process for stamplng up a one-piece sheet-metal clamp comprising gt a heavy-gauged body member equipt with drawn bosses and longitudinally grooved to suspend high-tension electrical conductors, ground wires or other cables therein.

, The primary object of my metho'dis to 1b economically fabricate a simple and substantial clamp body preferably provided with one or more integrally formed suspension straps having pocketed bosses associated n therewith, and to accomplish this purpose by 1%? a series of relevant stamping steps as distinguished from making the same articleby a casting method. The metal'in the 'cast type of clamp is not always homogeneous and uniformly soundbut it may readily be given an intricate body shape in heavily reenforced thicknesses that is often diflicult to duplicate in a stamping.

In the present nstance, the sheet-metal M blank is carried thrufa series of intermediate shapes in stepwise fashion, that progressively head toward and facilitatethe formation of the desired finished product, to the end that no abrupt short bending is allowed to tear the metal during the stamping process.

Wherever a relatively sh'arp corner radius needs to be formed up, this particular region is restruck in animproved manner, allwithout subjecting the required expensive dies to excessive wear or abnormal breakage risk.

The sequence of reshaping steps herein taught, assumes considerable importance when applied to rapid, flawless production of an inherently complicated stamping, such as a clamp body or the like. This article is usually given small overall dimensions but must be fabricated from relatively heavy stock running well over in thickness in order to provide for s'ufficient structural rigidity againstv the antioipatedcla-mp loadings. I i

The aim of the present invention is to de+ vise novel die means and to introduce dis K0 tinctive features of manipulation whereby U the cited difficulties may be overcome and a thoroughly reliable run of product obtained at a low production cost.

Reference is had to the accompanying three sheetsof drawings which are illustrative of a specific embodiment of my invention, together with dies that maybe used in stamp ing up clamps of the character indicated, and

' in which drawings:

Fig. 1 shows an elevational side-view of my clamp assembly as equipt with a keeper and adapter link.

Fig. 2 represents a top or plan view of my completed clamp body; and Fig. 3 is a transverse sectional view as taken along line 3--3 of Fig. 1 to illustrate a clamp bolt detail.

Fig. 4 shows the contour ofv a sheet-metal blank out of which my clamp body may be formed.

Figs. 5, 6 and 7 are perspective views of the successive shapes through which said blank is preferably carried in forming up the completed clamp body that is depicted in Fig. 8.

I Fig. 9 representsa plan View of the princlpal bottom die block required to fabricate my stamped clamp body, while Fig. 10 is a sectional View taken along line 10'1O of Fig. 9.

. Figs. 11 and 12 respectively disclose an elevational and a plan view of the top punch which cooperates with said die block inshaping up the clamp body.

The modified punch member similarly shown in Figs. 13 and 14, is also adapted to cooperate with said die block for the purpose of restriking or squaring the pocket corners of my clamp body. 2

Referring in detail to Figs. 1 to 3, these show the stampedsheet-metal article which it is desired to produce. ts more novel structural features reside in the grooved body member 10, which may in turn be equipt with a cooperating keeper 11 and a plurality of U or J type clamping bolts such as 12, that are shown grippingly assembled about the conductor 13..

My finished body member comprises a pair of laterally spaced sidewalls 14A and 14B and an interconnecting bottom wall or seat element 15. The respective terminals of the plementary suspension members are usually perforated at 18 to receive the support pin 18A therethrough, which in turn may carry the adapter link 19 in the conventional manner.

Formed in the respective side-walls and spaced lengthwise of the body groove in straddled relation to the respective suspension straps, are shown complementary tubelike bolt bosses, each comprising a semi-cylindrical pocket wall 21 having a transverse closure or foot wall 22 that is preferably kept fiat and aligned with the bottom of the groove in the merged fashion shown in the drawings. The marginal edge of said foot wall is filleted at 20 where it intersects with the interior of the upstanding boss wall 21.

Turning now to my improved stamping process for making the clamp body heretofore described, Fig. 4 discloses a preferred elliptical contour for the fiat blank as punched out of suitable sheet-metal, and as such may comprise an elongated groove-forming center region23C whileeach of the ends thereof is respectively shaped to provide for a rounded lip-forming element such as 23B. Each. longitudinal edge 23A of said center region is provided with a laterally disposed wing-like element 24 which may be initially pierced at 18. These wings are subsequently reshaped to constitute the parallel suspension strapsl'fAand 17 B. A smoothing up of theblank by grinding or the like, is found to prevent breaking the stock edges while the blank is being formed up into the required rather complicated final shape.

It is preferred to carry said blank through the successive shapes represented in Figs. 5, 6 and 7 and if so desired, these steps may be performed during a single stroke of the stamping press. In Fig. 5, there is initiated a series of spaced indentations 26 at each point around which it is intended to locate a boss; whereupon theblank center region may be partially grooved and the complementary wings. thrown toward. each other into V- shaped formation while the respective outermost ends of the still relatively flat lip elements 23B are being depressed away from the mouth of said V as indicated.

In Fig. 6 the U-ing operation of the suspension straps is substantially completed eX- cept that the respective lip-forming portions 2313 still remain undished; in Fig. 7 said lips have been given a trough-shape and the bolt pockets completed by inturning the longitudinal lip edges into the merged relationship with their respectvie curled tube-like bosses shown in the last named figure.

-I have found it expedient to provide a well rounded nose edge for the first entered punch tip that initially forms up the filleted marginal portion of the foot wall 22, otherwise prolonged localized stretching on the part of the surrounding pocket corner is likely to tear out and cause abnormal wastage in defective stampings. In order to obviate such difficulty and still provide for the desired sharp interior corner formation, it is preferred to restrike said fillet'edregion through the useof my improved punch means.

Referring to Figs. 9 and 10, these disclose a bottom die block 27 together with a pressure pad 27A, by which all of the foregoing operations may readily be carried out in association with said block and a suitable power driven press. Figs. 11 and 12 show the primary drawing punch 28 adapted to successively shape up my blank until the form represented by Fig. 7 is reached.

The modified punch 29 differs from punch 28 in that its lowermost perimeter is recessed at 30 so as to come in direct thrusting contact with the free upstanding edges of the respective pocket walls 21. During the restriking operation,-the respective uppermost pocket wall edges lying closely adjacent to each side of the respective suspension straps, are subjected to heavy downward thrust or coining operation. This expedient serves to drive said walls downward while reaching into the pocket interiors to square up the face of the foot wall 22 and sharpen the fillet around the perimeter thereof.

It now remains to punch out the bolt holes 31 in one or-more of the flattened pocket walls, which mayreadily be accomplished by the use of suitable piercing dies of the multiple punch type. With this, my clamp body is made ready to have a suitable keeper and bolts assembled therein.

As will be understood, various changes in the details of clamp structure or mode of die manipulation may be resorted to in carrying out the described fabrication method, and while it is generally preferred to adhere to the operative steps as recited, the same result might also be obtained when the order thereof is partially reversed or otherwise modified, all without departing from the spirit and scope of my invention heretofore set forth and more particularly pointed out in the appended claims, viz:

1. The method of stamping a one-piece suspendable clamp body or the like, which method includes the making of a flat sheet metal blank comprising an elongated center regionwhose end portions are respectively shaped into a lip-forming region while the opposite longitudinal side-edges of which center region are respectively provided with an overhanging suspension strap forming element, then spacedly indenting said center fill posed between lip-forming end regions, said intermediate region having a suspension strap-forming element overhanging from each of its opposite longitudinal edges, then spacedly indenting said center region inwardly of each such longitudinal edge in a straddled relation to the respective strap elements, and which indenting step is followed by an upturning of the free strap ends toward each other into a U-shaped profile while drawing each of the marginal blank portions lying exteriorly beyond the respective indentations into partially formed upstanding pocket side-walls that are unitedly merged with the respective upturned strap edges lying contiguous thereto.

3. The method of stamping a one-piece suspendable clamp body or the like, which method includes making a sheet-metal blank comprising an elongated center region interposed between lip-forming regions and which intermediate region has a suspension strapfcrming element overhanging from each of its opposite longitudinal edges, then spacedly indenting said center region inwardly of each such longitudinal edge in a straddled relation to the respective strap elements, and which indenting step is followed by an upturning of the free strap ends toward each other into a U-shaped profile while drawing each of the marginal blank portions lying exteriorily beyond the respective indentations into partially formed upstanding pocket sidewalls, and lastly, inturning the longitudinal edges of the respective lip-forming regions to impart a trough-shaped profile thereto and completing the formation of the respective upstanding pocket walls by unitedly merging the latter walls with their respective innermost trough-shaped lip elements lying contiguous thereto.

4. The method of stamping a one-piece suspendab-le clamp body or the like, which method includes making a sheet-metal blank comprising an elongated center region interposed between lip-forming regions and which intermediate region has a suspension strap-forming element overhanging from each of its opposite longitudinal edges, then spacedly indenting said center region inwardly of each such longitudinal edge in a straddled relation to the respective strap elements, and which indenting step is followed by an upturning of the free strap ends toward each otherinto a U-shaped profile while drawing each of the marginal blank portions lying exteriorily beyond the respective indentations into partially formed upstanding pocket side-walls, the bottom edge of each such side-wall being bridged by a transverse ly disposed foot wall element and the intersecting corner re ions thereof being initially given a relatively large fillet radius, and thereupon inturning both complementary longitudinal edges of the respective lipforming regions into a trough-shaped profile and completing the formation of the respective upstanding pocket'walls, and lastly, entering the mouth of one such pocket with a punch-like restriking implement serving to reduce the aforesaid fillet radius while simultaneously exerting a driving thrust upon the upstanding free edge of the completed side-wall of said one pocket.

5. The method of stamping a one-piece clamp bodyorthe like, which method includesmaking a flat sheet-metal blank of elongated contour, then spacedly indenting the center region of said blank inwardly of the longitudinal edges thereof, and which indenting step is followed by inturning each of the marginal blank portions lying exteriorly beyond their respective indentations into a pair of oppositely disposed upstanding pocketed side-walls of which the respective bottommost edges are bridged by a transversely disposedfoot wall element and the intersecting corner regions thereof each being initially given a relatively large fillet radius, and thereupon restriking the respective fillets to reduce the radius thereof while depressing the upstanding free edge of their pocket sidewalls to facilitate reforming said radii. V

In testimony whereof, I have herewith set my hand this 13th day of May, 1931.

- FLOYD D. WENN. 

